Pinfall detection means



Dec. 14, 1965 D. F. UECKER 3,223,414

PINFALL DETECTION MEANS Filed May 31, 1962 2 Sheets-Sheet 2 UnitedStates Patent Ofi ice Patented Dec. 14, 1965 3,223,414 PINFALL DETECTIONMEANS Donald F. Uecker, Spring Lake, Mich., assignor to BrunswickCorporation, a corporation of Delaware Filed May 31, 1962, Ser. No.199,034 10 Claims. (Cl. 273-52) This invention relates to new and usefulimprovements in bowling pin detecting systems.

More particularly, the invention relates to bowling pin detectionsystems and devices for determining whether a bowling pin is standing ona bowling lane bed on a pin spot or within a predetermined areasurrounding the pin spot.

It is the general object of the invention to provide a new and improveddetecting system for bowling pins.

Another object is to provide a detecting means for use in detecting pinshaving magnets therein and, more -particularly, for use in detectingstanding pins having vertically positioned magnets at the lower end oftheir central axes.

A further object is to provide such detecting devices with so-calledreed type switches or relays, with means for normally biasing the reedswitch to increase its sensitivity and with additional means forextending the area within which pins may be detected.

Other objects and advantages will become readily apparent from thefollowing detailed description, taken in connectionwith the accompanyingdrawings, in which:

FIG. 1 is a fragmentary plan view of the pin support ing portion of abowling lane bed with a preferred form of the invention installedthereon;

FIG. 2 is an enlarged fragmentary vertical view along line 2-2 of FIG.1, showing a preferred form of the invention;

FIG. 3 is a horizontal view along line 3-3 of FIG. 2;

FIG. 4 is a view similar to FIG. 1, with a modified form of theinvention installed on a bowling lane bed;

FIG. 5 is a view similar to FIG. 3, but on a reduced scale, of themodified form of the invention;

FIGS. 6 and 7 are graphs; and

FIG. 8 is a wiring diagram of a portion of a detecting system includingindicating lights.

While there is illustrated and described herein a preferred form of theinvention together with a modification thereof, they are shown with theunderstanding that they are for the purpose of disclosing the principlesof the invention and are not to limit the invention to the particularforms. The scope of the invention will be pointed out in the appendedclaims.

As shown in the drawings, 10 represents the pin supporting end of thebed of a bowling lane, and has the customary ten pin spots 11 forlocating pins 12 as shown in FIG. 2. The somewhat triangular areas 13indicate approximately the areas in which standing pins will be detectedby the form of the invention illustrated in FIGS. 1 to 3.

The invention is directed to a system for detecting and indicating thepresence or absence of pins in the ten areas 13 adjacent the ten pinspots 11 when the pins are provided with magnets 15, and detectingdevices 16 under the pin spots 11 are sensitive to the magnet 15 in astanding pin 12 but not to a fallen pin or the absence of a pin.

The bowling pin 12 is shown with an axially positioned cylindrical barmagnet 15 having its lower end approximately flush with the pin base 17.

In FIGS. 1 to 3 the detecting device 16 is shown as comprising a reedswitch 18 positioned below and coaxially of the pin spot 11. Leads 19and 20 connect with the reed switch contacts 21 and 22 respectively, anda biasing coil 23 surrounding the envelope 24 of the switch has leads 25and 26 at its ends. The arrangement of such switches in a circuit willbe described hereinafter.

In order to extend the sensitive area of the detecting device, theinvention contemplates the provision of a magnetically conductive meansor structure intermediate the switch 18 and the pin spot 11. In FIGS. 2and 3 such means is in the form of a spider having iron pole pieces ormembers 27 extending upwardly and outwardly from an integrally formedcentral plate 30 located immediately above the upper end of the switchand below an associated pin spot. The upper ends of the pole pieces areprovided with integral horizontal portions 31 to facilitate attachmentto the underside of the bed 10 by screws 32. A detecting device of thisform is sensitive to pins standing Within a substantial area around apin spot, as for example the triangular area 13 in FIG. 3, when themagnet 15 in the pin is positioned vertically therein and with its lowerend exposed, and the associated reed switch 18 is located coaxially ofthe pin spot and provided with a biasing coil.

In the modified form illustrated in FIGS. 4 and 5, the magneticallyconductive means is shown as comprising a central iron plate 30 and sixoutwardly and upwardly extending integral pole pieces or members 27having attaching portions 31'. With this form of metal spider thesensitive area of the detection device is more in the nature of thehexagons 13'.

Considering a two-pole magnet such as 15, of length L, the magneticfield is most intense between the poles along the magnetic axis, but ifthe magnet were inserted completely into a bowling pin, such field mightbe inaccessible for detection purposes. The field strength diminishesgenerally at all points more remote, but that field lying generallyoutside the ends of the magnet diminishes more slowly than thattransverse to the magnetic axis, and at a distance from the magnetgreater than L the endwise field is the stronger, being twice as strongat distances much greater than L.

It follows that a preferred magnet embodiment consists of a cylindricalbar magnet whose magnetic axis coincides with the longitudinal pin axisand one of whose ends is flush or nearly so with the pin base. With thisarrangement, the field generally downward from a standing pin is asintense as possible and that from a lying pin is relatively weaker andat right angles. Also, there are no azimuth effects resulting fromturning a standing pin on its longitudinal axis, as might happen afterseveral settings by the usual pinsetter machine.

It is preferable to use Alnico V for the magnetic material in the pin asit is among the most energetic materials available. Its magneticcharacteristics require that, for its most efficient functioning, itslength be about four times its diameter. It has been found that such amagnet in diameter by 1 /2" long in a tenpin is adequate to operate thedetection system, and that this size can be accommodated in the hole ina pin base as customarily supplied by the trade, without additionalmachining and at low cost.

Other magnetic materials might also be used provided the material can beconveniently fitted into the pin and will produce sufiicient energy.

A reed switch such as 18 consists generally of two thin, permeable,conductive reeds 21 and 22 whose adjacent ends overlap in thelongitudinal direction with a slight gap in the transverse direction.The outer reed ends connect into an electric circuit, for which the gapconstitutes a normally open circuit. Such constructions are commerciallyavailable, and are attractive because of their low cost, freedom frompivot joints, and their hermetically sealed, inert gas atmosphere forcontact protection.

They are, therefore, a preferred construction although functionallysimilar constructions might also be used.

If such a switch is placed in a magnetic field with its longitudinalaxis more or less in the direction of the field, the relatively highpermeability of the reeds causes a local increase in field strength andthe appearance of magnetic poles at the cantilevered ends of the reeds.The magnetic poles cause the reed ends to be attracted to each other, asis well known, with a force that increases rapidly as the gap is closed.At some field strength the magnetic attraction is sufficient to overcomethe stiffness of the reeds and the gap closes rapidly and completely.These relations are depicted in FIG. 6. The magnetic forces resultingfrom three different intensities of magnetic field are shown as curvedlines Ba, Bb and Be. In the case of the low field intensity Ba, themagnetic force can deflect the reeds only to point A, short of closure.At an intermediate field of strength Bb, the reeds would partially closeto point B. At a particular higher field intensity Bc, the magneticcurve would become tangent to the spring constant line at C and the gapwould close completely with surplus energy as shown by the area D and aresidual force producing contact pressure. As the fields were reduced,the contacts would remain closed, as at E, until no excess force orenergy were available, at which time the contacts would spring apartagain. This snap action is highly desirable to prevent contact burningand to provide shock and vibration resistance. It can be made as slightor pronounced as desired by varying the stiflness of the reeds and themagnetic proportions.

These relations lead to the conditions shown in FIG. 7 for a particularswitch. Line Bc indicates the field strength required to close theswitch, i.e., the upper line of FIG. 6. Ba indicates the drop out field,i.e., the lower line of FIG. 6. By providing a bias field associatedwith the subdeck equipment, the switch can be put in the intermediatecondition B of FIG. 6 before the flux from the pin is applied. By addingsufficient bias field to move point B very close to point C, only aslight incremental field from the pin is required to operate the reedswitch. The reed switches are insensitive to field polarity and wouldoperate as well at Bc and Ba, but if the pin magnets are all insertedwith a given polarity, only one direction need be considered.

Generally, it is not desirable that the detection system be equallysensitive at all times. The mechanical shock and vibration of pinfallsuggest that the detection system be activated after each ball is thrownonly after the pins have assumed essentially rest position, and the factthat the pinsetter may subsequently re-spot or sweep the standing pinssuggests that the results of the interrogation be stored in a memorysuch as a bank of holding relays.

Four different bias examples are indicated in FIG. 7. In Example I, abias 70 slightly less than Ba is applied, with the result that theoperating pin field is reduced from Bc to little more than Bc-Ba. InExample II, the switch is closed by a bias pulse 71 greater than Bc,subsequently the bias is reduced to 72 just under Ba, and only if astanding pin contributes a field to equal Ba will the switch remainclosed. This approach has the shortcoming that during the secondinterval the switch has little surplus energy and may be of highresistance. Accordingly, in Example III the bias 73 is increased to avalue between Ba and Ba for readout. My preferred method is shown inExample IV, in which the bias pulse 74 approaches Be. It has theadvantage of requiring no more pin field than in Examples II or III,results in low resistance, vibration-resistant contact, and can becompleted in a shorter interval with simpler bias switch gear.

The above assumes that the bias field and the pin magnet field arecooperative in their effect on the reed switch; although there is nooperational advantage to be gained, the polarity of the bias field mightbe chosen to oppose the pin magnet field and increased so as to beslightly greater than Be or Ba as the case may be. In such case, closureof the reed switch would signify a fallen pin and vice versa.

With a x 1 /2 Alnico V magnet, the reed switch mounted vertically withits upper tip about 5" below the playing surface, and bias conditions asin Example IV above, it is possible to detect a standing pin over abouta generally circular area of 3 /2 radius. The sensitive area ispreferably extended by using a magnetic means extending from the regionof the switch toward the playing surface. In the preferred embodiment asshown in FIGS. 2 and 3, and with the bias adjusted so that a fallen pindoes not close the switch, a sensitive area about as shown at 13, with a6 extreme radius has been obtained. The 5" radius of the pole pieces,circularly arranged as represented at 75, the 5" depth of the switchbelow playing surface, and the number, exact angle, or cross sectionalarea of the pole pieces are not critical.

Preferably the switch and its associated bias coil are supported fromthe spider plate 30 by a coil spring 33 for convenience as well as itsvibration isolation action.

FIGURE 8 is a fragment of a circuit diagram showing a pin detecting andindicating system embodying a plurality of reed switches 18 providedwith biasing coils 23. The coil leads 26 are all connected to a livewire 35 extending from one terminal of a 12 volt D.C. source 36. Thecoil leads 25 are connected to individual adjustable trim bias resistors37, the other ends of which are connected to a common line 38 which inturn is connected to the other side of DC. source 36 through anadjustable fine bias resistor 39, an adjustable coarse bias resistor 40and a manaully operable switch device 41.

Lines 42 and 43 represent a source of AC. controllable by a normallyclosed switch 44 in line 42. Leads 19 from the reed switches connectwith line 42. Relays 45 are provided, one for each pin spot on the bed,however, only five are shown in the fragmentary diagram of FIG. 6. Theserelays have coils 46, the left-hand ends of which are connected to thereed switch leads 20 and by leads 47 to relay-operated, normally openswitch members 48 which, when closed, act to complete holding circuitswhich include wires 49 extending from switch contacts 50 to the line 42.Armatures for the relays include rods 51 which are connected to operatethe switch members 48 to engage the contacts 50 when the relays areenergized, the rods normally being returned to the positions shown bysprings 52.

Each relay includes additional switches 53 and 54. The switches 53 areconnected in series by wires 55 and may be used in a circuit to indicatestrikes and spares. Switches 54 have contacts 56 also connected to wires49 and have switch members 57 connected by wires 58 to one terminal ofindicating lights 60 which have their other terminals connected by awire 61 to line 43. This arrangement results in the indication byillumination of lights 60 of the reed switches which are closed andcause energization of corresponding relays 45.

A capacitor may be utilized as at 63 to limit the rate of currentincrease in biasing coils 23, there-by to avoid shock excitation andconsequent vibration of reeds 21 and 22.

Thus it has been shown how a relatively simple and inexpensive pindetecting mechanism having small magnets in the base of the pins andreed switches positioned below the pins and sensitive to the presence ofthe magnets in the pin operates through a circuit to indicate standingbowling pins. Also, further improvements such as a magnetic meansbetween the magnets and the reed switches, and electrical bias on theseswitches have been described to provide a more effective and usefuldetecting system. Further a relatively simple circuit, as shown, hasbeen devised to provide for the biasing of the reed switches to permit asmall magnetic field caused by the presence of a standing bowling pin toactuate the detec ion mea s and to use the signals for indicatingpinfall or for other purposes.

I claim:

1. A detector for a bowling pin containing a vertical permanent magnetcomprising: a bowling alley having a pin spot thereon, a magneticallyactuated reed switch located vertically beneath said bowling alley pinspot and in an upright position, a metal structure located beneath andaround said spot and effective to produce conducting paths for magneticforces from such a pin standing on or near said spot to the switch, saidstructure comprising a plurality of metal members extending radiallyoutwardly and upwardly from an integral joining member locatedimmediately above the switch, and means forming a magnetic bias on saidswitch operable when energized to partially close it.

2. A detector for a bowling pin containing a vertical permanent magnetcomprising: a bowling alley having a pin spot thereon, a magneticallyactuated reed switch located vertically beneath said bowling alley pinspot and in an upright position, a metal structure located beneath andaround said spot and effective to produce conducting paths for magneticforces from such a pin standing on or near said spot to the switch, andmeans forming a magnetic bias on said switch operable when energized topartially close it.

3. A detector for a bowling pin containing a vertical permanent magnetcomprising: a bowling alley having a bed with a pin spot thereon, amagnetically actuated reed switch located vertically beneath saidbowling alley pin spot and in an upright position, and a magneticstructure between the pin spot and the switch eflective to enlarge thearea on the bed on which such a bowling pin could stand and stil affectthe magnetically actuated reed switch.

4. A pin detector for a bowling pin containing a permanent magnettherein with one pole above the other when the pin is standingcomprising: a bowling alley having a bed with a pin spot thereon, a reedtype switch lo cated in upright position coaxially of said bowling bedpin spot and vertically beneath it, means for producing a bias magneticfield on the switch, and a magnetic structure between the pin spot andswitch effective to enlarge the area on the bed on which such a bowlingpin could stand and still maintain the switch closed, said structurecomprising a portion immediately adjacent the upper end of the switchand portions extending outwardly and upwardly :from said first-mentionedportion.

5. A pin detector for a bowling pin containing a permanent magnettherein with one pole above the other when the pin is standingcomprising: .a bowling alley having a pin spot thereon, a reed typeswitch located in upright position coaxially of said bowling bed pinspot and vertically beneath it, and means for producing a bias magneticfield on the switch.

6. A pin detector for a bowling pin containing a per manent magnettherein with one pole above the other when the pin is standingcomprising: a bowling alley having a pin spot thereon, a magneticallyactuated reed type switch located in an upright position coaxially ofsaid bowling pin bed spot and vertically beneath it.

7. A bowling pin detection means for detecting standing pins havingmagnets therein, comprising: a bowling alley having ten triangularlyarranged pin spots thereon; a magnetically operable circuit controldevice beneath each pin spot responsive to a pin standing thereabove;and a magnetic structure beneath each pin spot around the axis thereoffor assisting flux from a standing pin to operate the circuit controldevice associated therewith; said magnetic structures each defining apolygonal detection area enlarged relative to the pin spot with which itis associated,

in which a pin will operate said device, said pin detection areas beingoriented relative to each other without overlap and with limitedclearances therebetween.

'8. In combination with a bowling alley having a plurality of pin spotsat positions where pins are set upright on the alley for bowling, a pindetector for detecting the presence or absence of bowling pins on saidpin spots and in a predetermined area therearound comprising: a bowlingpin for each pin spot, each bowling pin containing a coaxial magnet; amagnetically operable vertically positioned reed switch for each pinspot, each reed switch having an elongate non-magnetic envelope with twoaligned overlapping contact reeds therein, said reed switches each beinglocated coaxially of one of said pin spots and vertically spaced beneaththe respective pin spot; a metal spider for each pin spot, each spiderhaving a central plate located immediately above the switch associatedwith the respective pin spot and below said pin spot, and said spiderseach including iron pole pieces extending upwardly and outwardly fromthe central plate thereof to the lower surface of said bowling alley;means forming a magnetic bias on each said switch including a coilsurrounding the respective switch envelope and an electric circuitconnected to each coil, each circuit providing a current path to itsrespective coil when the circuit is completed to partially close therespective switch; and an indicating electric circuit .for each pinspot, each indicating circuit including one reed switch associated withthe respective pin spot, each of said indicating circuits .being adaptedto be completed when the reed switch therein is closed by the efiects ofthe respective pin magnet.

9. Bowling pin detecting means comprising: a magnetically operable reedswitch having an elongate nonmagnetic envelope with two alignedoverlapping contact reeds therein; a metal spider associated with saidreed switch, said spider having a central plate located immediatelyabove the switch with iron pole pieces extending upwardly and outwardlyfrom the central plate to define a pin detection area of triangularconfiguration; and means for providing a magnetic bias on said switchincluding a coil surrounding said envelope.

10. Bowling pin detecting means comprising: a magnetically operable reedswitch having an elongate nonmagnetic envelope with two alignedoverlapping contact reeds therein; a metal spider associated with saidreed switch, said spider having a central pla-te located immediatelyabove the switch with iron pole pieces extending upwardly and outwardlyfrom the central plate to define a pin detection area of hexagonalconfiguration; and means for providing a magnetic bias on said switchincluding a coil surrounding said envelope.

References Cited by the Examiner UNITED STATES PATENTS 1,606,164 11/1926 Garvin 200-96 X 2,194,146 3/ 1940 Kaiserman 27-346 2,585,153 2/1952Metz 273-1Q6 2,922,994 1/ 1;960 Kennedy 340- 282 X 2,966,561 12/ 1960Durant 27'3126 3,039,771 6/ 1962 :Bablouzian et al. 27-3-44 X 3,099,4477/ 1963 Isenberg et a1 27352 FOREIGN PATENTS 658,093 3/ 1938 Germany.

DELBERT B. LOWE, Primary Examiner.

6. A PIN DETECTOR FOR A BOWLING PIN CONTAINING A PERMANENT MAGNETTHEREIN WITH ONE POLE ABOVE THE OTHER WHEN THE PIN IS STANDINGCOMPRISING: A BOWLING ALLEY HAVING A PIN SPOT THEREON, A MAGNETICALLYACTUATED REED TYPE SWITCH LOCATED IN AN UPRIGHT POSITION COAXIALLY OFSAID BOWLING PIN BED SPOT AND VERTICALLY BENEATH IT.